1. Field of the Invention
The present invention relates generally to a wheel angle adjustment apparatus for an automobile suspension system and, more particularly, to a wheel angle adjustment apparatus for an automobile suspension system, which has a structure that allows toe and camber angles of wheels to be easily adjusted.
2. Description of the Related Art
As well known to those skilled in the art, a suspension system for an automobile is a device that couple wheels to an automobile body. A suspension system absorbs impact and vibration transferred from a road surface while the automobile is in motion, thus enhancing the riding comfort and stability of the automobile.
Such a suspension system is classified into a single body type suspension system, in which left and right wheels are integrally coupled to each other through an automobile axle, and an independent type suspension system, in which left and right wheels are independently operated. Conventional suspension systems include a spring to absorb shocks transferred from a road surface and a shock absorber that prevents free vibration of the spring, thus enhancing riding comfort and an arm or link to control the operation of the wheels.
In addition, there is a torsion beam suspension system, which is a unique hybrid of the single body type and the independent type. In the torsion beam suspension system, left and right trailing arms are coupled to each other by one unit that is called a torsion beam. The torsion beam suspension system is characterized in that the length of a link is longer than that of a strut suspension system and that of a double wishbone suspension system, and the number of bushings that may become an oscillating shaft is lower than that of the strut suspension system and that of the double wishbone suspension system.
Furthermore, the torsion beam suspension system can reduce friction hysteresis during movement of the suspension and provide a smooth comfortable ride. In addition, because it has a simple structure and a reduced number of elements, a high level of expertise is not required when designing the system, and the manufacturing costs and weight are reduced. Also, superior stability in driving the automobile is ensured. Therefore, conventional torsion beam suspensions have been used as rear suspension systems for small automobiles for many years.
As shown in FIG. 1, in such a torsion beam suspension system, a pair of trailing arms 1 and 1′ is coupled to each other by a torsion beam 2. A pair of joints 3 and 3′, each having a bushing, is provided on front ends of the trailing arms 1 and 1′, respectively. The front end of each trailing arm 1, 1′ is pivotably mounted to an automobile body (not shown) through each joint 30, 30′.
Furthermore, a spindle bracket 4, 4′ is welded to the rear end of each trailing arm 1, 1′. A wheel W, W′ is coupled to each spindle bracket 4, 4′ by a wheel bracket 5, 5′.
Moreover, a suspension spring 6, 6′ is provided between the automobile body and each trailing arm 1, 1′. A shock absorber 7, 7′ is provided on the rear end of each trailing arm 1, 1′ at a position spaced apart from each spindle bracket 4, 4′ by a predetermined distance.
Referring to portion R1 of FIG. 1 and to FIG. 2, an interposition plate 8 is provided between each spindle bracket 4, 4′ and each wheel bracket 5, 5′. The inclination of each wheel bracket 5, 5′ from a lengthwise direction (with respect to the front and back of the automobile) and from a vertical direction (with respect to the height direction of the automobile) is adjusted by changing the thickness of the interposition plate 8 through cutting. Therefore, the toe angle and the camber angle of each wheel W, W′ are determined.
For reference, a toe angle means an angle between the longitudinal axis of the automobile and each wheel, a front portion of which is angled inward or outward when viewing the automobile in a plan view. The toe angle of each wheel can be set to a previously designed value by adjusting the forward and backward angle of the associated interposition plate 8. The camber angle means an angle between the vertical axis of the automobile and each wheel, an upper portion of which is angled inward or outward. The camber angle can be set to a previously designed value by adjusting the vertical inclination of the associated interposition plate 8.
As such, in the conventional torsion beam suspension system having the above-mentioned structure, the front ends of the pair of trailing arms are pivotably mounted to the automobile body. However, the conventional torsion beam suspension system does not have a link serving to adjust the wheel alignment between the wheels and the automobile body, unlike other suspension systems (for example, multi-link suspension system). Therefore, the toe angle and camber angle, set when manufacturing an automobile, cannot be adjusted.
Thus, the conventional torsion beam suspension system is problematic in that if the wheel of an automobile having the conventional torsion beam suspension system becomes undesirably misaligned after the automobile is delivered from a warehouse, it is impossible to compensate for such wheel misalignment.